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The Testosterone and Metabolism Relationship

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In order to maximize results from your muscle building and fat loss program you need to understand the role that hormones play. If you increase your knowledge of important hormones you can adapt your training and diet to really boost your progress.

Testosterone – the primary male androgenic hormone – boosts strength, muscle mass and virility. It also plays an important role in energy production and metabolism.

In this article we’ll tell you how optimizing your T levels will help you burn more fat and outline the linear relationship between the two. We’ll also give you our best 5 ways to boost your metabolic rate through training and diet.

Read on to find out more…

What is Testosterone?

Testosterone is a hormone that is produced in the Leydig cells of the testes and the ovaries in women.

It is one of five classes of steroid hormones that plays a vital role in a number of biological processes that relate to male characteristics. Other steroid hormones include mineralocorticoids, progestogens, estrogen and glucocorticoids.

Testosterone has two main effects on your body tissue – it helps you develop and maintain male characteristics such as hair growth, voice deepening and strength. It also has androgenic effects that include slowing down protein breakdown and speeding up protein metabolism – big regulators of metabolism.

Normal total T levels for a man fall between 300-1000 ng/dL. If levels fall below 300 then you have clinical hypogonadism, or ‘low T’. Low male hormone levels can lead to loss of muscle, strength and sex drive, and an increase in metabolic disease risk. It can also lead to excess weight gain and ‘belly’ fat. 

As your metabolic rate underlies all indicators of health, it is important that you keep T levels as optimized as possible in order to maintain your fat and muscle levels.


Key Point: Your metabolism underlies all aspects of optimizing hormonal health.

How Does Testosterone Regulate Metabolism?

Metabolic rate refers to the speed at which you break down stored energy to be used by the body. It is related to all of the chemical processes that occur throughout the body in order to keep you alive.

These chemical processes require energy. The higher your metabolic rate, the the easier you find it to break down stored energy ready to be used for daily activities.

A number of studies have shown that those with low T levels have an increased change of weight gain. One study, published in Clinical Endocrinology [1] suggested that obesity is believed to be one of the most frequent associates of low T. The study also suggested that the relationship between metabolic rate and testosterone is pretty much linear – as one goes up, the other comes down.

These claims were also backed up by another study which suggested that there is an inverse relationship between fat mass and free T levels [2]. As such, metabolic rate is strongly correlated with T levels.

A high metabolism means having normal T levels, but it also means having low estrogen, prolactin and cortisol levels too – all of these hormones play a destructive role in that they decrease T if elevated for a prolonged period of time. If this happens, they combine to lower your metabolism as well as other side effects – lack of motivation, anxiety and poor sleep quality for example. You really need to avoid these to maintain a healthy physique.

When T is functioning properly it plays a more protective role in the body, in that it assists in creating energy and decreasing destructive hormones.

As we’ve already mentioned, steroid hormones are produced from cholesterol. Although the conversion is quite complex, cholesterol firstly converts to pregnenolone, then dehydroepiandrosterone (DHEA) before becoming testosterone.

Where the metabolism connection comes into play is the link between these conversion pathways and the thyroid hormone T3. When cholesterol is available, T3 combines with vitamin A to form pregnenolone.  As the primary metabolic rate regulating gland in the body, the thyroid also plays a significant role in metabolism and in energy regulation.

Without enough thyroid hormone, cholesterol cannot convert into pregnenolone. So if your metabolism is low, and you don’t produce enough T3, you can’t produce enough T either. You’ll also be leaving a fair amount of unused cholesterol accumulating in your blood as well. 


Key Point: Optimizing testosterone helps to boost your metabolic rate, build muscle and improve physical health.

What Can You Do to Boost Your Metabolism?

Coincidentally, the same tips that boost testosterone levels also to boost metabolic rate. Here are the most important ones:

#1. Weight train on a regular basis

Your basal metabolic rate (BMR) – the amount of energy you use at rest – is controlled by the amount of lean tissue you have – muscle is a metabolically active meaning the more you have, the higher your metabolism will be.

You don’t need to be looking at adding huge slabs of muscle to ramp up your fat burning potential, but the leaner and more muscle you have the better. Introducing weight training into your exercise program is essential for this process.

#2. Don’t undereat

Crash diets shock the body into clinging on to its fat stores for survival – it would rather sacrifice muscle for energy instead and retain fat for as long as possible. But this makes your BMR plummet. When you start to eat properly again you just pack it on as extra fat stores as your metabolic rate is much lower. Remember, muscle is key for BMR.

Many crash diets also force you to completely omit a full food group from your diet. This can lead to nutrient deficiencies and health complications.

#3. Optimize your nutrients

Micronutrients such as magnesium, zinc and vitamin D are all essential for sufficient testosterone levels. An estimated 2 billion people in the world have zinc deficiency. Without it you can’t manufacture enough testosterone or growth hormone – another important hormone that keeps body fat low and boosts muscle growth. Likewise, many people have low levels of vitamin D – not only does this nutrient boost T levels, it helps break down stored energy for use too.

#4. Try HIIT training

The next time you try cardio, introduce small but intense interval periods – 20-30 seconds of all-out sprinting or cycling will force your body to consume more oxygen for energy. Recover and repeat. This has a dramatic effect on your metabolic rate and can also boost muscle mass too. It is far shorter, but much more effective than standard cardio.

#5. Sleep

Restricting sleep sees a massive increase in cortisol – the destructive hormone that blunts testosterone and contributes to belly fat. A study by Taheri et al [3] found that sleep was an important regulator of metabolic rate, reporting that poor quality sleep decreased levels of leptin – a hormone that increases hunger and reduces satiety.

The study reported that those who only managed 5 hours sleep per night had 15.5% lower leptin levels, causing overeating and contributing to weight gain.

Summary – Testosterone and Metabolism

Metabolism refers to the process of breaking down stored energy for use throughout the body. The higher you metabolic rate, the more efficient you are at utilizing fat for energy use, and as such are more likely to have a healthy body composition.

Testosterone plays a key role in maintaining metabolic rate and research suggests that there is a linear relationship between the two. Testosterone also protects against destructive hormones such as estrogen and cortisol that can decrease metabolism and cause bell fat and weight gain.


  1. Saboor Aftab, SA et al. The Role of Obesity and Type 2 Diabetes Mellitus in the Development of Male Obesity-associated Secondary Hypogonadism. Clin Endoc. 2013; 78(3): 330-337
  2. Dandona, P et al. A practical guide to male hypogonadism in the primary care setting. Int J Clin Pract. 2010; 64(6): 682-696
  3. Taheri, S et al. Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index. PLoS Med. 2004; 1(3): e62